list [解决办法] List<Model.Model_UserProjectID> list = new List<Model_UserProjectID>(); foreach (String str in UserIdList) { Model.Model_UserProjectID model = new Model_UserProjectID();//放循环里面 model.ProjId = int.Parse(ProjId); model.UserId = int.Parse(str); list.Add(model); } [解决办法] 为什么不这样呢? List<Model.Model_UserProjectID> list = new List<Model_UserProjectID(); foreach (String str in UserIdList) { Model.Model_UserProjectID model = new Model_UserProjectID(); model.ProjId = int.Parse(ProjId); model.UserId = int.Parse(str); list.Add(model); } [解决办法]